<template>
    <div>
        <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
            <div class="iconfont header-abs-back">&#xe606;</div>
        </router-link>
        <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
            <router-link to='/'>
                <div class="iconfont header-fixed-back">&#xe606;</div>
            </router-link>
            景点详情
        </div>
    </div>
</template>

<script>
export default {
    name: 'detailHeader',
    data() {
        return {
            showAbs: true,
            opacityStyle: {
                opacity: 0
            }
        }
    },
    methods: {
        handleScroll() {
            // 处理兼容性问题
            const top = document.documentElement.scrollTop || document.body.scrollTop || window.pageYOffset
            if (top > 60) {
                let opacity = top / 140
                opacity = opacity > 1 ? 1 : opacity
                this.opacityStyle = { opacity }
                this.showAbs = false
            } else {
                this.showAbs = true
            }
        }
    },
    mounted() {
        window.addEventListener('scroll', this.handleScroll)
    },
    destroyed() {
        window.removeEventListener('scroll', this.handleScroll)
    }
}
</script>

<style lang="stylus" scoped>
    @import '~styles/varibles.styl'
    .header-abs
        position: absolute
        left: 0
        top: 0
        width: .8rem
        height: .8rem
        line-height: .8rem
        text-align: center
        border-radius: .4rem
        background: rgba(0, 0, 0, .8)
        .header-abs-back
            color: #fff
            font-size: .4rem
    .header-fixed
        z-index: 99
        position: fixed
        top: 0
        left: 0
        right: 0
        height: $headerHeight
        overflow: hidden
        height: $headerHeight
        line-height: $headerHeight
        text-align: center
        background: $bgColor
        font-size: .32rem
        color: #fff
    .header-fixed-back
        position: absolute
        top: 0
        left: 0
        width: .64rem
        font-size: .4rem
        text-align:center
        color: #fff
</style>
